In the prior art, an inverter is used to convert a direct current voltage on a direct current data bus to one or more alternating current signals that control an electric motor. In certain prior art configurations, the inverter comprises one or more power switching semiconductors that may fail in an open state or a closed state. If one or more power switching semiconductors fail in a closed state, a short circuit may be established between the opposite polarity terminals of the direct current data bus or between a direct current terminal and a normally alternating current output of the inverter, which can damage a winding of the electric motor or other circuitry within the inverter. Thus, there is need to detect a short circuit in the direct current bus at a lower test voltage than the operational voltage of the inverter to minimize damage to the electric motor or the inverter.